kernel/linux.git/tools/arch/x86/lib, branch v5.15.208

x86/insn: Fix PUSH instruction in x86 instruction decoder opcode map

2024-06-16T11:39:31+00:00

[ Upstream commit 59162e0c11d7257cde15f907d19fefe26da66692 ] The x86 instruction decoder is used not only for decoding kernel instructions. It is also used by perf uprobes (user space probes) and by perf tools Intel Processor Trace decoding. Consequently, it needs to support instructions executed by user space also. Opcode 0x68 PUSH instruction is currently defined as 64-bit operand size only i.e. (d64). That was based on Intel SDM Opcode Map. However that is contradicted by the Instruction Set Reference section for PUSH in the same manual. Remove 64-bit operand size only annotation from opcode 0x68 PUSH instruction. Example: $ cat pushw.s .global _start .text _start: pushw $0x1234 mov $0x1,%eax # system call number (sys_exit) int $0x80 $ as -o pushw.o pushw.s $ ld -s -o pushw pushw.o $ objdump -d pushw | tail -4 0000000000401000 <.text>: 401000: 66 68 34 12 pushw $0x1234 401004: b8 01 00 00 00 mov $0x1,%eax 401009: cd 80 int $0x80 $ perf record -e intel_pt//u ./pushw [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.014 MB perf.data ] Before: $ perf script --insn-trace=disasm Warning: 1 instruction trace errors pushw 10349 [000] 10586.869237014: 401000 [unknown] (/home/ahunter/git/misc/rtit-tests/pushw) pushw $0x1234 pushw 10349 [000] 10586.869237014: 401006 [unknown] (/home/ahunter/git/misc/rtit-tests/pushw) addb %al, (%rax) pushw 10349 [000] 10586.869237014: 401008 [unknown] (/home/ahunter/git/misc/rtit-tests/pushw) addb %cl, %ch pushw 10349 [000] 10586.869237014: 40100a [unknown] (/home/ahunter/git/misc/rtit-tests/pushw) addb $0x2e, (%rax) instruction trace error type 1 time 10586.869237224 cpu 0 pid 10349 tid 10349 ip 0x40100d code 6: Trace doesn't match instruction After: $ perf script --insn-trace=disasm pushw 10349 [000] 10586.869237014: 401000 [unknown] (./pushw) pushw $0x1234 pushw 10349 [000] 10586.869237014: 401004 [unknown] (./pushw) movl $1, %eax Fixes: eb13296cfaf6 ("x86: Instruction decoder API") Signed-off-by: Adrian Hunter Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20240502105853.5338-3-adrian.hunter@intel.com Signed-off-by: Sasha Levin

tools arch: Update arch/x86/lib/mem{cpy,set}_64.S copies used in 'perf bench mem memcpy'

2022-05-15T18:18:51+00:00

[ Upstream commit 35cb8c713a496e8c114eed5e2a5a30b359876df2 ] To bring in the change made in this cset: f94909ceb1ed4bfd ("x86: Prepare asm files for straight-line-speculation") It silences these perf tools build warnings, no change in the tools: Warning: Kernel ABI header at 'tools/arch/x86/lib/memcpy_64.S' differs from latest version at 'arch/x86/lib/memcpy_64.S' diff -u tools/arch/x86/lib/memcpy_64.S arch/x86/lib/memcpy_64.S Warning: Kernel ABI header at 'tools/arch/x86/lib/memset_64.S' differs from latest version at 'arch/x86/lib/memset_64.S' diff -u tools/arch/x86/lib/memset_64.S arch/x86/lib/memset_64.S The code generated was checked before and after using 'objdump -d /tmp/build/perf/bench/mem-memcpy-x86-64-asm.o', no changes. Cc: Borislav Petkov Cc: Peter Zijlstra Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

x86/insn: Use get_unaligned() instead of memcpy()

2021-11-18T18:16:30+00:00

[ Upstream commit f96b4675839b66168f5a07bf964dde6c2f1c4885 ] Use get_unaligned() instead of memcpy() to access potentially unaligned memory, which, when accessed through a pointer, leads to undefined behavior. get_unaligned() describes much better what is happening there anyway even if memcpy() does the job. In addition, since perf tool builds with -Werror, it would fire with: util/intel-pt-decoder/../../../arch/x86/lib/insn.c: In function '__insn_get_emulate_prefix': tools/include/../include/asm-generic/unaligned.h:10:15: error: packed attribute is unnecessary [-Werror=packed] 10 | const struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr); \ because -Werror=packed would complain if the packed attribute would have no effect on the layout of the structure. In this case, that is intentional so disable the warning only for that compilation unit. That part is Reported-by: Stephen Rothwell No functional changes. Fixes: 5ba1071f7554 ("x86/insn, tools/x86: Fix undefined behavior due to potential unaligned accesses") Suggested-by: Linus Torvalds Signed-off-by: Borislav Petkov Acked-by: Masami Hiramatsu Tested-by: Stephen Rothwell Link: https://lkml.kernel.org/r/YVSsIkj9Z29TyUjE@zn.tnic Signed-off-by: Sasha Levin

x86/insn, tools/x86: Fix undefined behavior due to potential unaligned accesses

2021-09-24T10:37:38+00:00

Don't perform unaligned loads in __get_next() and __peek_nbyte_next() as these are forms of undefined behavior: "A pointer to an object or incomplete type may be converted to a pointer to a different object or incomplete type. If the resulting pointer is not correctly aligned for the pointed-to type, the behavior is undefined." (from http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1256.pdf) These problems were identified using the undefined behavior sanitizer (ubsan) with the tools version of the code and perf test. [ bp: Massage commit message. ] Signed-off-by: Numfor Mbiziwo-Tiapo Signed-off-by: Ian Rogers Signed-off-by: Borislav Petkov Acked-by: Masami Hiramatsu Link: https://lkml.kernel.org/r/20210923161843.751834-1-irogers@google.com

tools arch: Update arch/x86/lib/mem{cpy,set}_64.S copies used in 'perf bench mem memcpy'

2021-05-10T12:01:00+00:00

To bring in the change made in this cset: 5e21a3ecad1500e3 ("x86/alternative: Merge include files") This just silences these perf tools build warnings, no change in the tools: Warning: Kernel ABI header at 'tools/arch/x86/lib/memcpy_64.S' differs from latest version at 'arch/x86/lib/memcpy_64.S' diff -u tools/arch/x86/lib/memcpy_64.S arch/x86/lib/memcpy_64.S Warning: Kernel ABI header at 'tools/arch/x86/lib/memset_64.S' differs from latest version at 'arch/x86/lib/memset_64.S' diff -u tools/arch/x86/lib/memset_64.S arch/x86/lib/memset_64.S Cc: Borislav Petkov Cc: Juergen Gross Signed-off-by: Arnaldo Carvalho de Melo

tools/insn: Restore the relative include paths for cross building

2021-03-17T19:17:05+00:00

Building perf on ppc causes: In file included from util/intel-pt-decoder/intel-pt-insn-decoder.c:15: util/intel-pt-decoder/../../../arch/x86/lib/insn.c:14:10: fatal error: asm/inat.h: No such file or directory 14 | #include /*__ignore_sync_check__ */ | ^~~~~~~~~~~~ Restore the relative include paths so that the compiler can find the headers. Fixes: 93281c4a9657 ("x86/insn: Add an insn_decode() API") Reported-by: Ian Rogers Reported-by: Stephen Rothwell Signed-off-by: Borislav Petkov Tested-by: Ian Rogers Tested-by: Stephen Rothwell Link: https://lkml.kernel.org/r/20210317150858.02b1bbc8@canb.auug.org.au

x86/insn: Make insn_complete() static

2021-03-15T12:03:46+00:00

... and move it above the only place it is used. Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20210304174237.31945-22-bp@alien8.de

x86/insn: Add an insn_decode() API

2021-03-15T10:05:47+00:00

Users of the instruction decoder should use this to decode instruction bytes. For that, have insn*() helpers return an int value to denote success/failure. When there's an error fetching the next insn byte and the insn falls short, return -ENODATA to denote that. While at it, make insn_get_opcode() more stricter as to whether what has seen so far is a valid insn and if not. Copy linux/kconfig.h for the tools-version of the decoder so that it can use IS_ENABLED(). Also, cast the INSN_MODE_KERN dummy define value to (enum insn_mode) for tools use of the decoder because perf tool builds with -Werror and errors out with -Werror=sign-compare otherwise. Signed-off-by: Borislav Petkov Acked-by: Masami Hiramatsu Link: https://lkml.kernel.org/r/20210304174237.31945-5-bp@alien8.de

x86/insn: Add a __ignore_sync_check__ marker

2021-03-15T10:00:57+00:00

Add an explicit __ignore_sync_check__ marker which will be used to mark lines which are supposed to be ignored by file synchronization check scripts, its advantage being that it explicitly denotes such lines in the code. Signed-off-by: Borislav Petkov Reviewed-by: Masami Hiramatsu Link: https://lkml.kernel.org/r/20210304174237.31945-4-bp@alien8.de

x86/insn: Add @buf_len param to insn_init() kernel-doc comment

2021-03-15T10:00:19+00:00

It wasn't documented so add it. No functional changes. Signed-off-by: Borislav Petkov Acked-by: Masami Hiramatsu Link: https://lkml.kernel.org/r/20210304174237.31945-3-bp@alien8.de